The Presidium Gem Computer Gauge uses an altogether different method for measuring specific gravity.

In lieu of the hydrostatic method common to our other devices, where the gem or mineral must be weighed in water, the Gemstone Estimator feature of this tool directly measures the volume of a cut  gemstone, and divides that into the weight of the stone to derive specific gravity.

The Gem Computer Gauge first prompts the user to select the type of cut among the following choices:  

	Round
	Oval
	Emerald
	Marquise
	Heart
	Pear
	Cushion
	Rectangular
	Cabochon

Then with the precision calipers, the user measures the length and width, or diameter, along with the depth of the stone.   You are then prompted to enter the weight of the stone.  The Gem Computer Gauge then computes the volume using internal formulas for the  particular geometric shapes.  Once the SG is computed, the Gem Computer Gauge retrieves matching gemstones from its internal database!

In my experience, this Geometric method for SG, while quick and easy, should be considered as an approximation only.

Other Features

GEMSTONES & SHAPES Covers 74 gemstones and 9 different shapes.

AUTO-MAGNETIC SHUT-OFF Auto-magnetic shut-off to save power when placed in carrying case. This power-saving feature is immediately activated when the gauge is placed in its carrying case.

Exclusive features - Direct carat conversion for round brilliant cut diamond. - Harden platform. - 0.01mm resolution. - Weight computation through direct measurement or keypad entry. - Universal serial bus interface with computer. - CD-Rom with 133 gemstones.

S.G. Dictionary Retrieve the specific gravity of specific gemstone directly from the S.G dictionary by just entering the name of the stone.

Gemstone estimator Identify an unknown gemstone material by entering the measurement and weight.
1 year factory warranty

Size :  Length - 3.8" x Width - 2.4" x Thickness - .63" Weight : 4 ounces or 120 grams without battery

Included

• Presidium Computer Gauge
• Battery pre-installed
• Jewelry Attachment for measuring mounted stones
• USB Cable
• Mini CD with Software
• Storage and Carrying Case
• Polishing Cloth
• User Handbook

This item typically ships within 1 business day.